Car surges at a stop


#1

My PT Cruiser runs fine, doesn’t miss while driving, but when I stop at a light etc. it surges in drive or neutral and more so with AC on. I took it to mechamis they said needed tune up cost over $2,000 as they had to pull manifold. surge started again. They said spark plug bad, repalced for $20.00 surge stopped for a couple of days and is doing it all the time now. Quite anoying What is going on??


#2

I have never even seen the engine of a PT Cruiser, but surging is often caused by a vacuum leak. I can only speculate that the reason that they pulled the intake manifold was because they thought that the vacuum leak was at the manifold, and they replaced the manifold gasket. That is a LOT of money for a tune-up and a manifold gasket.

The fact that it seemed better for a couple of days after they replaced the spark plug is surprising. If there is actually a problem in the area of the manifold (cracked, improperly machined surface) and they still suspected it, they may have tried some sealant or tightening it down a bit more when they replaced the spark plug, and that helped for a while.

You definitely need a better mechanic. If you can access the manifold, you might try spraying something flammable around it. Something like starting fluid (ether). If spraying around the intake manifold changes the engine speed or stops the surge, you have a vacuum leak. Be careful not to burn yourself.


#3

I agree that you need a new, competent mechanic. In addition to the “tune-up” being grossly overpriced, if you returned a few days, weeks, or even months later and were told that one of the spark plugs was bad, the mechanic certainly owed you a new spark plug gratis, after he had picked your pocket for $2,000. for a “tune-up”.

You need to find a new mechanic who is honest, as well as competent–two qualities that your present mechanic seems to lack. Like Manolito, I suspect that your problem all along was a vacuum leak, which is VERY cheap to repair in most instances. To “throw” $2,000 worth of parts and labor at a car, and yet be unable to resolve this problem, does not speak well for your mechanic.


#4

Thank you for your answers. I am taking it to another mechanic next week.
Now I have a new noise. Right before I come to a stop, I hear a soft clunk>